When did the Mawlid first appear?

Question:

"When did the innovation of the Mawlid (first) appear Shaykh Muhammad?"

Answer:

"In the fourth century; meaning that the three virtuous (best) generations passed by and not a single person celebrated it. It (first) occurred in the fourth century and increased, spread and intensified in the seventh century. Many works in that regard, and all praises belong to Allah, have been authored, which clarify the beginning of this innovation, its root and its rank within the (Islamic) legislation, and there is no basis for it in Allah's legislation."

Shaykh Muhammad bin Saalih al-'Uthaymeen, may Allah have mercy upon him